U.S. Pat. No. 5,846,889 “Infrared Transparent Selenide Glasses” discloses alkaline earth Ga and/or In-containing selenogermanate glasses comprising at least 5% RSe (where R=alkaline earth), 0.5-25% Ga2Se3 and/or In2Se3, 20-70% GeSe2 with the provision for rare earth dopants. However, due to the relatively Ga- or In-poor nature of the compositions, it is likely that rare-earth dopants in such glasses are clustered and, therefore, characterized by reduced luminescent efficiency.
It would be advantageous to expand the range of the glassforming region of modified selenogermanate glasses which may allow for greater flexibility in tailoring glass properties such as characteristic temperatures (e.g. Tg), thermal expansion coefficient, refractive index, conductivity, etc. that may be important for specific applications.